A case having concave chamfers, especially applied in 3C electronic products, sometimes has an extremely shallow (about 10 mm) concave depth, which is unfavorable for the conventional metal stamping mold design. The concave chamfer will be stuck, difficult to combine and stamped with an extremely shallow concave when releasing mold. Therefore the concave chamfer presently is made of plastic material, and is made by injection molding or vacuum forming. Compared with the metal case, although the plastic case has better elasticity of forming plasticity, however there are defects of bad radiating, insufficient rigidity and heavy plastic sense. Additionally, another conventional technique to manufacture concave chamfer metal case uses a male mold manufactured by a rubber material and uses the elasticity of rubber to conveniently release mold. However, after used for a period of time, the rubber material will lose its elasticity gradually to be embrittled. In other words, the life of the rubber male mold is short. Further, controlling the forming quality is not easy due to the deformation of rubber itself, so the rubber male mold still has a lot of defects. Besides, the concave chamfer structure can also be manufactured by lost-wax casting. However, for the cases of consuming electronic products necessary for mass production, the lost-wax casting no doubt is the largest obstruction for output promotion or raising the producing speed, so it is not practicable.
In order to overcome the drawbacks in the prior art, a mold set for manufacturing a case and the method thereof are provided. The particular design in the present invention not only has better heat-dissipating effect compared with the conventional plastic case, but also increases the rigidity of the case due to higher strength of metal. In addition, as the metal has higher specific weight than the plastics, it has more weight than the plastics, and due to low specific heat, the slightly cool sense makes a user unable to put it down.